Rifle sight



Sept.6,1966 "R. Apmohimp 3,270,418-

RIFLE smm' Filed April 21,1964

FIG.2 W

INVENTORS QBERT A I m? HONY a 5122?? BY 2a X/{f ATTORNEY 3,270,418 RIFLESIGHT Robert A. Simeone, 121 Linwood St., Milford, Conn., and

Anthony B. Simeone, 100 Broadfield Road, Hamden,

Conn.

Filed Apr. 21, 1964, Ser. No. 361,402

3 Claims. (Cl. 33-56) This invention relates to an improved gun sightand more particularly to an improved sight of the general type cover byour Patent 2,881,524.

The sighting of a gun, and particularly of a rifle, often has to bereadjusted for distance, and when used in hunting this adjustment mustbe effected extremely rapidly and preferably without having to take theshooters right hand and trigger finger away from the gun. "Unless thiscan be done precisely and very rapidly with one hand the gun can oftennot be accurately aimed at rapidly moving game.

In the past various gun sights have been adjusted in small discreteincrements, referred to as clicks from the audible noise-made. In otherwords if a rifle is properly sighted for a hundred yards and must thenbe sighted for two hundred or two hundred and fifty yards the sight mustbe raised by a definite number of clicks. Unfortunately this is not asimple matter because the trajectory of the rifle bullet is in the formof a parabola which is drastically modified by the effect of airresistance on the bullet after it leaves the muzzle of the gun. Needlessto say the trajectory is in the form of a curve of a highly nonlinearequation. The clicks however are linear. The number of clicks .totransform the sighting from 100 yards to 200 yards is considerably lessthan that required to transfer the sighting from 200 to 300 yards and soon. Of course tables are available for particular rifle calibers andparticular loads of propellant explosives, and if the shooter memorizesthese tables he can rapidly count clicks. In practice however this hasnot proved practical except for target shooting where there is unlimitedtime to check a table. As a result there has been no practical gun sightWhich could be adjusted quickly and accurately to meet the manyvarieties of ballistic trajectories.

Our prior patent, referred to above, dealt with an attempt to solve thisproblem. Essentially in the patent the sight itself, such as the commonpeep sight, was mounted on an L-shaped bracekt capable of moving up anddown. The bracket extended down over along the receiver of the rifle,and was provided with a driving pin. It moved in a metal member with asuitable dovetailed groove to assure against lateral play, this memberbeing bolted to the receiver. Two other disc shaped members were boltedto a central opening in the same member referred to above, one of themwith a spiral groove of more or less arbitrary shape. This disc could beturned by a second disc attached thereto through two screws in slots topermit relative movement of the second disc which was cup shaped andcarried indicia on its outer periphery. When the disc with the spiral isturned the pin on the sight bracket which engages with the spiral grooveis moved up carrying the sight with it. As the spiral groove was to someextent arbitrarily chosen the indicia did not form a linear scale. Butonce proper adjustment had been there is no problem of adjusting a capor of dealing with a scale which at best is nonlinear.

made the sight could be rapidly moved by the shooter by turning thediscs and observing the indicia against a fixed mark on the receiver.

Our prior patent represented a great advance in rapid sighting butsuffered from a serious problem. It is with an improvement of the typeof sight just described that the present invention deals.

Two drawbacks were the arbitrary choice of spiral groove and theadjustment method which was very coarse and very slow. Also theadjustment could not be brought back readily and easily to a particularposition. In the present invention the cap and groove disc form aunitary structure, which will be referred to as a rotatable cam member,and there is provided'a linear scale. The groove groove spiral is chosenso that it is an'accurate involute of the actual trajectory. Now thelinear scale, which is easily read, corresponds to a linear sightingrange and In the present invention the member in which the sight bracketmoves is not bolted to the receiver of-the rifle but in turn slides in adovetail groove on an additional memberwhich is bolted to the gun. Thissecond member'is provided with a micrometer screw abutting against thesliding member carrying the grooved disc and permitting a precisevertical adjustment thereof for initial setting or zeroing in. As themicrometer screw head carries a scale it is easy to readjust toaparticular value.

The reasons for the improvement obtained with the present invention liein the fact that the trajectory of the bullet is enormously affected bythe retarding action of the atmosphere. This increases so rapidly, asthe cube of muzzle velocity, that the actual trajectory is changed onlya little by changing muzzle velocity with the same type of gun, that isto say the same caliber and general bullet configuration. Thusvariations due to propellant charge can be very closely approximated byan actual linear displacement of the spiral groove. Putting it anotherway the present invention was made possible by the fact that thetrajectories of the same caliber and type of bullet with different loadsof propellantwere a practically parallel family of curves. Accordingly,the drastic departure from ideal trajectory, a true parabola in.avacuum, has been used in the present invention to make possible a simpleadjustment for different propellant loads without upsetting the accuracyof the linear scale on the grooved element which is turned. The presentinvention therefore represents a rather unusual case where a theoreticalenormous complication of the trajectory is made to perform a highlyuseful effect. Ordinarily when ideal conditions are departed fromcompensation is required. In the present case this does not occur andthe sight of the present invention, which is extremely accurate withvarious loads in actual shooting through the atmosphere, would becompletely inoperative *under ideal conditions in a vacuum. Ditffferentloads would then change the parabola completely because the shape of aparabolic trajectory is determ-ineduniquely by initial velocity and thevalue of gravity and no sight can be made which performs the valuableadditional functions that are possible in the present sight.

i i -t i It is not possible to use the same sight forf guns of thepresent invention adds no complication thereto.

It has been stated above that the present invention includes as one of,its essential features that the spiral groove be an accurate involute of,the actualtrajectory. This presents no particular problems for eachgroove for each caliber. While it might be thought theoreticallypossible to compute mathematically the shape of the spiral, in practicethis is extremely difficult and it is much simpler and cheaper todetermine the involute experimentally by firing a gun from a machinerest at different distances. These show the amount by. which the sighthas to be raised for each range and these points then permit graphicallylaying out the shape of the spiral groove with ease in accordance withordinary machine design. Of course once a groove for a particular spiralis determined it is simplicity itself to reproduce it as many times asis desired.

It has been pointed out above that a linear displacement of the membercarrying the spiral permits corrections for different propellant loads.This is one of the important practical advantages of the presentinvention but it presupposes that the same caliber gun will have abullet. of more or less comparable characteristics. Sometimes there maybe special ammunition or special guns which sufficiently change thebullet characteristics so that it is behaving very much as a differentcaliber. In such cases it is very cheap to replace the member having thegroove with another one having a somewhat different spiral groovecorresponding to atypical ammunition. As this element is bolted onquickly with a central screw such interchanging can be 7 effectedrapidly, and thus the present sight is useful even where there may beoccasional uses of highly atypical ammunition.

It will be noted from what is stated above that the correction forammunition load by means of a micrometer screw is really a correctionfor muzzle velocity. With guns of the same type, for instance of thesame barrel length, all that is needed is a table for screw settingswith different loads. barrel length as well as propellent load anadjustment of the micrometer screw is necessary in going from a gun ofone barrel length to one of a very different one. This however presentsno problem as a table of micrometer screw scale settings for the newtype of gum is furnished with it and it is perfectly simple to set thescrew accordingly. This is an added advantage of the present inventionwhich permits adjustment to barrel length in a simple manner and withgreat precision. 4

The invention will be described ingreater detail in conjunction with thedrawings in which:

FIG. 1 is an isometric view with a sight shown exploded so that thevarious members are separated, and

FIG. 2 is a section through FIG. 1 along the line 2-2.

The gun receiver is shown at 1. To the receiver there is bolted a member5 fastened with two bolts 6 and provided with a dovetail groove 7. Thismember is not shown exploded in FIG. 1 but is shown in its actualposition bolted to the gun receiver. The member 5 is provided with anextension from which a micrometer screw 2 extends with a head 3 havingon its periphery a l The next member'8 slides in the dovetailed grooveof member 5 the slide being the male dovetail 9. The bottom of thismember when assembled strikes the end of the micrometer screw 2 and canbe moved with respect to member 5 a definite predetermined amount bymeans of the screw.

The other side of the member 8 carries a female dove- Since the muzzlevelocity is effected bytail or groove 10 and in this slides an L-shapedbracket 13 carrying a peep sight 11 in a slot 12, thmsight beingmoveablelaterallycfopwindage b means of the screwi ti This wiridage adjustmentis one of many conventional types and is not significantly. changed bythe present invention. Of course its mounting must be s uitable for theL-shaped bracket 13. The bracket carries a. pin 15 and central slot 16.The pin engages spiral groove 20 in a disc 19, in the form approximatelyof an involute of the trajectory, which is rotatable and which is boltedto a member 17 by bolts 24. The member 17 carries on its periphery ascale 18. -All of the movable members except the bracket 13 are-screwedtogether with a screw 21 engaging a threaded recess 22 in the member-8.The screw 21 extends-through the slot 16 of the bracket13, the length ofthe slot corresponding to maximum movement of the'bracket 13. v g

In use the sight is assembled, the micrometer screw 3 adjusted or zeroedin, at any known distance for the particular ammunition load and barrellength of the gun and then sighting is-effected" merely by turning themember 17, the scale 18 being readable against a mark 23 on the member8. Change of range requires only turning of the member -17 with one handuntil the correct range is read on the 'scale 18. This can be done veryrapidly, particularly as 'the scale is linear. When the shooter wishesto use different ammunition, that is to say ammunition with a differentpropellant load, he merely adjusts the head 3 of the micrometer screw 2to zero in, at any distance to which the member 17 is set.

The head 3 can be then set to the same reading whenever this particularkind of ammunition is. to be used under the same conditions, and thechange forgotten and after any setting of the head 3 the sighting of thegun is effected precisely as before. It should be noted that members 17and 19 cohstitute single rigid structure which can be moved as a unit byadjustment of the screw 2. This is an additional advantage over thesight described in our earlier patent. In that sight it .was necessaryto loosen two screws and move the cap with respect to the other portion.of the rotating member carrying the spiral groove, it is possible 'forthe scale to become out of adjustment with the groove. In the sight ofthe present invention this cannot occur as scale and groove are part ofa unitary whole, the members 17 and 19 and no slippage is possible whichcan occur if the adjusting screws in our earlier patent become loose.This feature is of importance though not as basic as the preciseinvolute shape of the spiral grooveand the possibility of micrometricadjust-ment. It is however an advantage of practical importance andmakes it impossible for loosening of screws to throw the sight out ofadjustment. It should be noted that the micrometer screw, as is the casewith this typeof mechanism has so fine a pitch and it provided with adetent 25 so that it is, for-all practical purposes, self locking andwill not move in ordinary use of the gun until the screw is deliberatelyturned to provide a new setting on the scale of its head 17.

When changing gun caliber screws-21 and 24 are unscrewed and anew disc19 substituted with a groove of the proper involute shape for thetrajectory of the new caliber.

We claim:

1. In a gun sight comprising a base plate adaptor to be secured to thereceiver of the gun, a sight supporting member, means permittingvertical sliding of said member with respect to the base plate, saidmeans including a rotatable cam member provided with a slot therein anda slot engaging projection on the sight supporting member,

the improvement which comprises,

(.a) the slot is in a form approximating an involute of the trajectoryof a bullet of the particular gun caliber in air, (b) a member slidablevertically in the base-plate and carryingon its opposite face a gr0ovein which. the

5 6 sight supporting member is slidably mounted for one a cam slotcarrying disc and the other a rotatable vertical movement, membercarrying the linear scale. (c) micrometric adjusting means connectingthe base plate to the member sliding therein and capable of ReferencesCited y the Elam!!!" :liding (the meniber vertically in accuratelyprede- 5 UN STATES PATENTS ermine amoun s, ((1) means for attaching thecam member to the memgfig :3 sliding in the base plate to form a unitarywhole, 2,671,966 3/1954 kcobscn et a1 (e) a direct reading linear scaleon the periphery of 10 2881524 4/1959 Slmeone et a] 33-665 the cammember. FOREIGN PATENTS 2. A gun sight according to claim 1 in which themicrometric means is provided with a scale showing relative 12238 1909.,Gmat Bmam' movement between the base plate and the member slidingLEONARD FORMAN Primary Examiner therein.

3. A gun sight according to claim 1 in which the ro- 15 HAROIAN,Assistant Examinertatable cam member is in two pieces bolted together,

1. IN A GUN SIGHT COMPRISING A BASE PLATE ADAPTOR TO BE SECURED TO THERECEIVER OF THE GUN, A SIGHT SUPPORTING MEMBER, MEANS PERMITTINGVERTICAL SLIDING OF SAID MEMBER WITH RESPECT TO THE BASE PLATE, SAIDMEANS INCLUDING A ROTATABLE CAM MEMBER PROVIDED WITH A SLOT THEREIN ANDA SLOT ENGAGING PROJECTION ON THE SIGHT SUPPORTING MEMBER, THEIMPROVEMENT WHICH COMPRISES, (A) THE SLOT IS IN A FORM APPROXIMATING ANINVOLUTE OF THE TRAJECTORY OF A BULLET OF THE PARTICULAR GUN CALIBER INAIR, (B) A MEMBER SLIDABLY VERTICALLY IN THE BASE PLATE AND CARRYING ONITS OPPOSITE FACE A GROOVE IN WHICH THE SIGHT SUPPORTING MEMBER ISSLIDABLY MOUNTED FOR VERTICAL MOVEMENT, (C) MICROMETRIC ADJUSTING MEANSCONNECTING THE BASE PLATE TO THE MEMBER SLIDING THEREIN AND CAPABLE OFSLIDING THE MEMBER VERTICALLY IN ACCURATELY PREDETERMINED AMOUNTS, (D)MEANS FOR ATTACHING THE CAM MEMBER TO THE MEMBER SLIDING IN THE BASEPLATE TO FORM A UNITARY WHOLE, AND (E) A DIRECT READING LINEAR SCALE ONTHE PERIPHERY OF THE CAM MEMBER.